Shadow economies are usually associated with illegal activity, such as drug dealing. But anecdotal evidence indicates that off-the-books work in today's job market includes personal and domestic workers, such as housekeepers and nannies.
"The jobs are in service industries from small food establishments to landscaping." said David Fiorenza, an economy professor at Villanova University. "Even the arts and culture industry is not immune to working off the books in areas of music and entertainment."
It also includes firms that hire hourly or day construction labor, information technology specialists and Web designers. Many who have a job that doesn't pay enough take another one that pays under the table.
"We've always had people who make income without recording it, so it's not really new," said Peter McHenry, an assistant professor of economics at the College of William & Mary. "But the fact that more and more people are doing it shows how bad the job picture is," he added.
The reasons behind the underground economy's growth are fairly simple, according to Gonzalez.
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"There's a lot of uncertainly about immigration changes and who will be legal, and about paying for Obamacare," she said, adding that most workers in the shadow economy are in the country illegally. "Government rules are keeping businesses from hiring."
A report from ADP Research Institute states that many employers, especially in low-wage businesses such as retail and food service, plan to reduce workers' hours to less than 30 a week to avoid having to offer health benefits through Obamacare (or pay a fine).
"This type of regulation could put more people out of work and into an underground economy," McHenry said.
But employers have their own agenda, according to Padilla.
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"Businesses are not angels, and they exist to make a profit," Padilla said. "They are going to do everything they can to keep costs down, and if that means paying people off the books, they will do it. The government doesn't really have the resources to track down every business that does this."
What the government is keeping track of is lost revenues. According to the Internal Revenue Service, about $500 billion in taxes were lost last year because of unreported wages, versus $384 billion in 2001.
"The effects of the underground economy are larger than we think," said David Fiorenza. "The result is less tax money paid to the various levels of government."
"Those working and not paying the taxes puts the burden on those who pay the tax," added Fiorenza. "Taxes could be lower if the government where able to capture the underground economy instead of raising taxes on those currently paying the various income and payroll taxes."
But the dangers of a shadow economy go beyond dollars and cents, analysts said. Workers who aren't on the books don't get Social Security or health benefits, and worse.
"People who do these types of jobs run the risk of getting exploited with lower pay or not being paid at all," Gonzalez said. "There could be more exploitation if more people are forced into this type of economy."
"Some income is better than none, but there is a reason we have certain regulations in place to protect workers and what they do," McHenry said.
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In the end, what's happening below the normal economy should not come as too much of a shock, according to Gonzalez.
"People are running out of patience when it comes to finding a job and losing income," Gonzalez said. "So it's not that surprising to have workers take jobs that are in the shadow economy. But it's a sign of how bad things are and how we have to get the real economy moving again."